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Publication Abstract from PubMed

Helicobacter pylori is a pathogenic bacterium that causes gastric ulcers and cancer. Among the diverse virulence genes of H. pylori, the IceA gene was identified to be expressed upon adherence to host cells. The IceA gene has two alleles, iceA1 and iceA2, which encode completely different proteins. IceA1 protein was shown to exert endonuclease activity, whereas IceA2 has never been analyzed at the molecular level. Based on a sequence analysis, IceA2 proteins differ in length depending on the strain and are classified into five groups (A-E). To structurally characterize IceA2, we determined the crystal structure of group-D IceA2 (IceA2(sD)) and performed a modeling-based comparative analysis of IceA2 groups. IceA2(sD) consists of three beta-sheet repeats and serially arranges them like the beta-propeller structure of the WD40 domain. However, each beta-sheet of IceA2 is stabilized using a unique structural motif that is not observed in WD40. Moreover, IceA2(sD) lacks an additionally appended beta-strand and does not form the Velcro-like closure of WD40. Therefore, IceA2(sD) adopts a curved rod-like structure rather than an enclosed circular structure in WD40. IceA2 proteins contain 1-4 beta-sheet modules depending on the groups and are modeled to be highly diverse in size and shape.

Structural analysis of the virulence gene protein IceA2 from Helicobacter pylori.,Cho HY, Cho H, Song WS, Yoon SI Biochem Biophys Res Commun. 2022 Jul 5;612:162-168. doi: , 10.1016/j.bbrc.2022.04.090. Epub 2022 Apr 25. PMID:35526497^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.